My aim is to defend the concept of sustainable development both against economists' interpretations that make it involve perpetual gains to human well-being, and against sceptical accounts that make its meaning vary from speaker to speaker, serving as a cloak for the status quo and the suggestion that it be discarded. The assumptions of the economists' interpretation are questioned, and the centrality among early advocates of sustainable development of sustainable practices and of sustainability being social and ecological as well as economic is used to support a different interpretation. On this interpretation, sustainable development involves the satisfaction of basic needs and comprises the precondition of economically, socially and ecologically sustainable practices. What is to be sustained is overtly practices and more basically intrinsic value. This account is shown to assist with solving conflicts between nature preservation and alleviation of poverty, solutions to which are argued to embody sustainable development even in the absence of prospects of ever-increasing quality of life for humanity. While this interpretation already counts against sceptical accounts, these are also shown to arise from the adoption of the radical concept of sustainable development by governments, international agencies and multinational business at the Rio Summit of 1992, and consequent re-interpretations. But the rational response is not discarding the concept but rediscovering the radical core and potential to which these various bodies are in theory committed